The external air conditioner unit is humming. Why is this happening?

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Now you’ve been using your air conditioner for a year, two... Everything seems to be fine: constant cold air gives comfort in the summer heat. But here, out of nowhere, there is an incomprehensible noise that does not go away after a day or a month. And then you thought, “why is the air conditioner humming?”

In our article we will tell you in detail why the uncharacteristic sound of the air conditioner appears, why it is connected with the external part and how to fix everything quickly and with your own hands.

For those in the know: at what levels is air conditioner noise normal?

Each household appliance has certain standards for industrial noise. They are measured in Decibels (DB) and should be specified in the device's operating instructions.

The noise during operation of the air conditioner should be within the following limits:

• 40 dB – during the daytime;
• 30 dB – at night (from 23:00 to 7 am).

This parameter is measured by a special device. If there is none, there is no need to buy it, just to take measurements once or twice. You can use these examples as a guide: the ticking of a wall clock is about 30 dB, and normal dialogue (half a tone) is close to 40 dB. If the air conditioner unit is really humming, let’s look further into the reasons and what to do.

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The outdoor unit of the air conditioner is noisy - how to solve the problem

Among the component parts, it is the external one that is subject to the greatest loads.Wind, dust and dirt, sun rays and many other factors - all this can affect the humming of the external unit of the air conditioner.

Each split system has in the outdoor unit:

• pump,
• fan,
• air cooler,
• TRV.

Why is the air conditioner humming? Most often this happens due to problems with the compressor and fan. They blow on the condenser, which cools the air for us. Parts have moving parts. Over time, the system wears out, which can cause the outdoor unit of the air conditioner to hum. But the problem may arise due to other factors.

If your split system outdoor unit is humming, refer to the list of possible breakdowns:

• There is no oil in the air conditioner crankcase - you need to add fluid;
• reduction of winding resistance (we will talk about this problem later);
• wear of components – it is possible to replace some parts or the entire external unit.

It is not possible to determine low resistance on your own, as special substances are needed. They are poured directly into the crankcase. The substance reacts to the acidity of the environment, which corrodes the starter winding. The problem occurs after several years of active use of the device, moisture ingress and rust on the components. If the reagent changes the color of the oil in the crankcase, then this is a clear sign - it’s time to completely replace the compressor.

The air conditioner is humming - the problem is in the fans. Their bearings often wear out. As a result, the rotor sags and touches the cover of the device, which causes an unpleasant sound. The most dangerous outcome is when the blades touch the condenser. Defects may appear or even a refrigerant pipe may burst.

When the split system is used in winter, a lot of ice from freezing condensate accumulates under the fan.The blades can also touch it, which is why the external unit of the air conditioner is noisy.